“Do you mean to tell me that your position is more important than 400,000 black people’s lives? Senator Humphrey, I know lots of people in Mississippi who have lost their jobs trying to register to vote,” the civil rights heroine Fannie Lou Hamer declared at the 1964 Democratic National Convention in Atlantic City, New Jersey, a little over a half century ago.

Lots of people think the really hot convention was Chicago 1968, when the Democratic Party, the city, and the entire country erupted in massive anti-war protests. But four years earlier, another incredible story unfolded: the saga of the Mississippi Freedom Democratic Party, which dared to come to Atlantic City and demand to be seated as legitimate delegates. The MFDP arrived at the height of Freedom Summer, when volunteers from all over the country went south, attempting to enforce African-American voting rights. (It was dangerous—people died doing this.) The March on Washington had taken place only one year before; the Selma-Montgomery March was a year away. (Interracial marriage was still illegal in 17 states.)

Hamer and the other MFDP delegates rode a Greyhound bus north, aiming to unseat their state’s “official” delegation—a white, racist, segregated faction that had ignored, subverted, and laughed in the face of laws meant to provide fair representation. “I had to leave the plantation where I worked in Sunflower County, Mississippi. Now if you lose this job of vice president because you do what is right, because you help the MFDP, everything will be all right. God will take care of you,” Hamer continued, pretty much reading Hubert Humphrey, the VP candidate, to filth. “But if you take [the nomination] this way, why, you will never be able to do any good for civil rights, for poor people, for peace, or any of those things you talk about. Senator Humphrey, I’m going to pray to Jesus for you.”

The Democratic Party leadership, afraid of losing the white Southern vote, tried to fob off the MFDP with lame, insulting compromises, which it angrily rejected. Sympathizers mounted an around-the-clock picket line on the boardwalk outside the convention center; perhaps most important, the Dems’ Credentials Committee’s deliberations were televised, which meant all of America could hear and see what was really going on.

John Lewis, one of the MFDP’s leaders (now a venerated congressman, he most recently led the sit-in on the House floor to demand gun control legislation), summed it up: “We had played by the rules, done everything we were supposed to do, had played the game exactly as required, had arrived at the doorstep, and found the door slammed in our face.”

Four years later, at the historic convention in Chicago, an integrated delegation was seated, and that was that.

Don’t be ashamed if you don’t know this story, if you have never heard of Hamer—so much of our history is hidden from us! But as the Democratic Convention gets under way today in Philadelphia, and a woman for the first time accepts the nomination for president from a major party on Thursday, let’s take a moment to honor Hamer and her incredible comrades, who rode a bus north to defy the odds and demand their seat at the table.